• Food Science and Preservation
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• v.12 no.5
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• pp.424-431
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• 2005

'Hongro' and 'Gamhong' apples grown at the Gochang-si in the southern part of Korea were harvested on September in 2002 for storage study. Each cultivar was divided into two groups of maturity based on the harvested date. Immature fruits were harvested 10 days early compared to fruits having proper maturity. This study was conducted to evaluate quality the change of 'Hongro' and 'Gamhong' apples newly bred by different storage methods with PE film package and CA conditions. A typical climacteric respiration pattern was observed in new variety 'Hongro' and 'Gamhong' apples stored at room temperature. The results indicated that fresh quality of the stored fruits in CA condition was better than that in other treatments during storage. Qualities of apples were least changed at CA storage of 3% $CO_2$ and 1% $O_2$. CA storage was effective in maintaining the freshness of 'Hongro' and 'Gamhong' for 16 weeks.

• Current Research on Agriculture and Life Sciences
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• v.33 no.1
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• pp.33-35
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• 2015

This study investigated the effect of AVG treatment on lipid material changes in the 'Hongro' apple epidermis. The internal ethylene concentration in 'Hongro' apples treated with $200mL{\cdot}L^{-1}$ AVG and stored at room temperature after harvest was significantly lower than that in 'Hongro' apples treated with $20mL{\cdot}L^{-1}$ Ethephon and the controls. During the same period, the emission of wax after the AVG treatment was also significantly lower than that after the other treatments. In conclusion, treatment with $220mL{\cdot}L^{-1}$ AVG two weeks before harvesting was found to be effective in improving and maintaining the quality of the 'Hongro' apples. Reducing the level of internal ethylene can delay the aging of fruit and inhibit the accumulation of wax in the fruit epidermis.

• The Korean Journal of Food And Nutrition
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• v.32 no.4
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• pp.364-370
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• 2019

This study was conducted to select cultivars and determine the harvest period suited for the availability of biological activities in unripen apple. To analyze effective the components in the apple (Malus domestica), three cultivars, 'Summerking', 'Hongro', 'Fuji' were harvested from 40~50 days after full bloom to harvest time. Soluble solid content increased gradually by ripening but titratable acidity decreased with ripening regardless of the cultivars. The total phenol content significantly reduced with ripening from May 30 to July 30 (p<0.05). Substantially, the total phenol content of 'Hongro' in May 30 was four times higher than that of 'Summerking' in the same period and ten times higher than that of 'Hongro' in August 30. The total flavonoid content reduced with ripening regardless of cultivars (p<0.05) and that of 'Hongro' in May 30 was significantly highest (p<0.05). The ascorbic acid content was the highest in 'Hongro' in May 30 (p<0.05). The contents of tannin and ursolic acid significantly reduced with ripening from May 30 to July 30 (p<0.05), while no significant difference was observed between Hogro and Fuji after July 30. Therefore, 'Hongro' harvested in May 30 was considered to be best in the utilization of the effective components of immature apple.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.445-451
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• 2012

The thinning effects of lime sulfur either alone or combined with fish oil on two apple cultivars 'Fuji'/M.9 and 'Hongro'/M.9 were investigated during two consecutive seasons. Either 1% or 2% lime sulfur at full bloom decreased the amounts of both terminal and axillary fruits compared with unsprayed 'Fuji' control trees in the first year. However, 1% or 2% lime sulfur did not decrease terminal fruit set in the second year. Only, triple applications of 1% lime sulfur significantly reduced the number of terminal and axillary fruits in both years. Multiple application of 1% lime sulfur was the most effective in thinning of 'Hongro'. In the first year, double or triple applications of 1% lime sulfur was effective in thinning terminal or axillary fruit, but one time applications of 1% or 2% lime sulfur was not reduced axillary fruit in 'Hongro' apple trees. In the second season, all treatments reduced terminal or axillary fruit in 'Hongro' clusters, except single application of 1% lime sulfur. Fish oil did not always improve the thinning effects of lime sulfur in 'Fuji' or 'Hongro' apple trees. None of treatments caused significant russeting in the harvested fruits. Most of thinning treatments had little effect on 'Fuji' or 'Hongro' fruit quality in terms of fruit weight, firmness, soluble solids concentration or titratable acidity.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.352-357
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• 2019

In this study, we investigated the limit temperature range which is effective for dormancy release of 'Hongro' and 'Fuji' apples during the endodormancy period. The germination rate was 50% or more in all treatments except of 'Hongro' $-5^{\circ}C$ treatment. The germination rate of 'Fuji' was 86.3% at the temperature of $-5^{\circ}C$. The concentrations of carbohydrate and mineral components were significantly different between treatments but did not show any tendency or specific change. However, the sorbitol contents of 'Hongro' $-5^{\circ}C$ treatment were higher at 29.62 mg/g than those of 'Fuji', which was not affected for dormancy release. The results of hormone analysis showed that ABA(abscisic acid) and JA(jasmonic acid) in 'Hongro' $-5^{\circ}C$ treatment were respectively 176.48 and 15.72 ng/g. ABA, JA and SA(salicylic acid) contents in 'Fuji' apple tree were significantly lower than those of 'Hongro'. As a result of this study, the limit temperature range effective for dormancy release was different according to the varieties, and 'Hongro' did not affect with 30.3% of germination rate at $-5^{\circ}C$. However, 'Fuji' is 86.3% even at $-5^{\circ}C$ it was suggested that 'Fuji' had a chilling accumulation for dormancy release.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.534-539
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• 2010

'Hongro' is early-mid maturing cultivar with good quality like 'Tsugaru' and it has not preharvest drop. The CAX1 gene was introduced into Korean apple cultivar 'Hongro' by Agrobacterium tumefaciens LBA4404 harboring pBI121 to obtain transgenic apple with enhanced Ca level. The CAX1 gene playing the role of $H^+/Ca^{2+}$ transporter from Arabidopsis thaliana increases Ca concentration in several plants. Regenerated transgenic lines were confirmed by polymerase chain reaction (PCR) analysis and Southern blot analysis of genomic DNA for the existence of CAX1 gene. Southern blot analysis of 'Hongro' transformants showed that two putative transgenic lines were integrated with CAX1 gene in genomic DNA. The CAX1 comparative expression levels of two transgenic lines were higher than that of non-transformant evaluated by comparative quantification analysis using a real-time PCR. These two lines were multiplied in vitro, and micro-grafted on apple rootstocks 'M.9' in the isolated greenhouse. Since two years after micro-grafting, the fruits came into bearing. Compared to Ca level of the non-transgenic 'Hongro', that of the CAX1 transgenic 'Hongro' in the flesh and leaves was higher.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.123-133
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• 2021

In order to use Osmia cornifrons more effectively in apples, we investigated the pollination effect and nesting activity of O. cornifrons on 'Hongro', the middle-season cultivar, and 'Fuji', the late-season cultivar. There was a significant difference in the nesting activity and pollination effect of O. cornifrons depending on the apple cultivar. The nesting activity, rate of trap nesting, and reproduction in 'Fuji' were 2.5, 1.5, and 3.8 times greater than in 'Hongro', respectively. The pollination effect according to cultivar 'Fuji' was 1.6 times greater than that of 'Hongro' in the central fruit set. In terms of the quality of fruit, the asymmetry index of 'Fuji' was 2.5 times lower than that of 'Hongro', and the number of apple seeds of 'Fuji' was 1.9 times greater than that of 'Hongro'. The main reason for this result was the air temperature. The activity of O. cornifrons was most affected by air temperature (R2 = 0.578). It is expected that the nesting activity and pollination effect are great in 'Fuji' (17.4-24.1℃) when the temperature during the blooming period is higher than that of 'Hongro' (12.5-20.2℃). Our study provides important information on stable apple production for apple cultivators, and can be used as an evidence for changes in flora and insect fauna caused by climate change.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.61-64
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• 2015

As an edible coating, carnauba shellac wax (CSW) and lemongrass oil (LO) solution was prepared to extend the shelf life of 'Hongro' apples. During storage, there were significant differences in the populations of total aerobic bacteria, yeast, and molds between the coated apples and the control samples. The weight loss and vitamin C loss of apples coated with the CSW-LO solution were lower than those of the control. These results suggest that CSW-LO coating can be an effective method for improving quality of 'Hongro' apples.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.481-487
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• 2010

The ripening behavior of three apple cultivars, 'Tsugaru', 'Hongro' and 'Fuji' was distinctive and the involvement of POLYGALACTURONASE(PG) in the fruit softening process was confirmed to be ethylene dependent. Fruit softening is genetically coordinated by the action of several cell wall enzymes, including PG which depolymerizes cell wall pectin. Also, loss of firmness is associated with increasing of the ripening hormone, ethylene. In this work, climacteric ripening of three apple cultivars, Tsugaru, Hongro and Fuji, producing different ethylene levels and ripening responses, was examined. Correspondingly in Fuji, a linear and basal ethylene level was observed over the entire period of measurements, and Tsugaru and Hongro displayed a typical climacteric rise in ethylene production. Transcript accumulation of genes involved in ethylene biosynthesis (MdACS3 and MdACO1) and MdPG1 was studied in Tsugaru, Hongro and Fuji cultivars. Expression of MdACO1 transcripts was shown in all three ripened apple fruits. However, the MdACS3 and MdPG1 were transcribed differently in these cultivars. Comparing the MdPG1 of 'Tsugaru', 'Hongro' and 'Fuji', structural difference was discovered by genomic Southern analysis. Overall results pointed out that MdACS3 and MdPG1 play an important role in regulation of fruit ripening in apple cultivar.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.63-70
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• 2021

Two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is one of the major pests in apple orchards. TSSM was known to show different population dynamics depending on apple cultivars. We tested the host plant preference and fitness of TSSM on the leaves of 3 apple cultivars, Fuji, Tsugaru, and Hongro. TSSM showed higher behavioral preference to Fuji than Tsugaru and Hongro, and showed a higher fecundity in Fuji. The immature development of this mite was the shortest in Fuji and longest in Hongro. Total fecundities were not significantly different among cultivars, but daily fecundity was higher and longevity was lower in Fuji. Hongro was the less preferred cultivar for TSSM, and showed the lowest fitness by life table parameters. These results could explain the possible mechanisms of differential population dynamics among apple cultivars. Further study including diverse apple cultivars currently available in Korea could help to deploy time- and cultivar- specific IPM tactics.